Electric switch



Jan. 15, 1929.

G. WHEAT ELECTRIC SWITCH Filed Aug. 25, 192s 0 3 l m u e, x k

m. a i A.

INVENTOR.

Patented Jan. 15, 1929.

UNITED STATES PATENT OFFICE.

GRANT WHEAT, OF MARLBORO, MASSACHUSETTS, ASSIGNOR TO KOEHLER MANUFAC- TUBING COMPANY, OF MABLBORO, MASSACHUSETTS, A CORPORATION OF MASSA- GHUETTS.

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Application filed August 25, 1926. Serial No. 131,401.

This invention relates to electric switches and will be herein disclosed as embodied in a switch designed especially for use inthe battery casing of a miners lamp.

The miners lamps used in the more progressive districts include a battery which is slung from the miners belt and an electric lamp supplied with current from said battery and mounted on the miners cap. These batteries are charged at a station or lamp house provided for that purpose, and for convenience in charging thebattery a switch usually is mounted in the battery casing, this switch being operable to connect the battery terminals either with the lamp or with the charging terminals as desired.

It is desirable that the miners be .prevented from operating this swtich but that it be readily operable by the attendant at the lamp house. To this end the present invention aims to provide a simple and reliable lock for the battery switch, it being understood, however, that constructions embodying this invention are not limited in their application to switches designed for the particular use above described.

The nature of the invention will be readily understood from the following description when read in connection with the accompanying drawings and the novel features will be particularly pointed out in the appended claims.

In the drawings, Figure 1 is aperspective view of a battery casing with the cover removed to show a switch construction embodyin this invention, and Fig. 2 is a plan .'view 0 the casing and switch mechanism,

the cover being removed.

i In theconstruction shown the casing comprises a main section 2 and a top 3 which is secured to the part 2 by a metal band 4. A chamber 5 is formed in the top 3 to receive the switch and its connections, this chamber normally being closed b a cover 6. The cover is secured to the casing at one end by a tongue 7 integral with the casing and entering a groove 8 in the end of the cover. At its opposite end the cover is fastened by a screw 9 passing throu h a hole 10 and into ahole 11, this screw aving a specially shaped head which fits in a socket in the top of the cover so that it is necessary to use a special tool in order to remove it and permit the opening of the cover. Preferably the battery casing and the cover '6 are made of vulcanite or some other insulating 1 material.

Theswitch mechanism provided by this lnvention comprises a disk 12 of insulating material mounted on a pivot screw 13 which is threaded into the top 3. This disk is proof the disk substantially flush therewith, and

forming the movable contact of the switch. Stationary contacts 17 and 18 are located at opposite sides of the disk. A conductor 19 connects thecontact 17 with a stud 20 -which projects through the cover 6 and terminates at the outer face'thereof, this stud forming a charging terminal. Another charging terminal 21 is connected by a conductor 22 to one terminal 23 of the battery. The opposite terminal 24 of the battery is electrically connected by a metal strap 25 to the pivot 13 for the switch disk 12. Another strap 26 connects the stationary contact 18 with a conductor 27 which runs to the lamp (not shown) the opposite terminal of this lamp being connected by the conductor 28 to the battery terminal 23.

The disk 12 and the extension 14 constitute, in effect, a switch lever. When this lever is in the position shown in Fig. 2, current flows from the battery terminal 24 through the strap 25, movable contact 16, stationary contact 18 and conductors 26 and 27 to the lamp, returning through the conductor 28 to the opposite battery terminal 23. This is the position in which the switch remains while the miner is using the lamp.

In order to charge the battery, the switch handle or thumb-piece 14 is thrown to the left, bringing the contact 16 into engagement with the contact 17 This cuts,off the .flow of.current to the lamp and connects the tion of the switch, therefore, the battery may be charged by placing it in a suitable charging apparatus, such apparatus having contacts to engage the outer ends of the terminals 20 and 21.

In order to lock the switch against operation by the miner or any other unauthorized person, a lock consisting of a dog 27 is mounted closely adjacent to one edge of the disk 12, this dog being pivoted on the screw 28 and having a tooth 29 arranged to enter a notch 30 formed in the edge of the disk 12. A spring 31 bears against the dog and tends to hold it in said notch, or in other words, tends to keep the switch locked. It will be observed that the lock is not only concealed but that the miner cannot obtain access to 1t. Provision is made, however, for releasing the look by placing a magnet in a predetermined position against the outer surface of the casing. It will be noted that the lock or dog 27 has arms or extensions 33 and 37 projecting in opposite directions therefrom. A stud 32 of iron or other magnetic material projects through the wall of the casing top 3, its inner end being located closely ad acent to the position normally occupied by the end of the arm 37 of the lock 27 Another piece 34. of iron or other magnetic material is also set into the wall of the casing 3 and is L-shaped, including a horizontal arm indicated at 34C and an upright arm 35 which projects into the chamber 5 and normally lies just in front of the extension 33 of the dog 27. When a magnet M is placed against the outer ends of the metal pieces 32 and 34, these parts become, in effect, extensions of the poles of the magnet and they transmit lines of force to points closely adjacent the arms 33 and 37 of the locking dog, thus causing this dog to swing about its pivot 28 and withdraw the tooth 29 from the notch 30. In other words, the lock is magnetically released. The thumb-piece 14 of the switch 12 may now be thrown to the opposite position from that shown in Fig. 2 thus making the necessary circuit connections to permit charging of the battery.

It is contemplated that when the lamps are delivered to the lamp house the attendant will unlock the switch of each lamp inthe manner above described, throw the switch into charging position and then place the battery in a charging rack. IVhen the attendant removes a battery from a charging rack to deliver it to the miner, he throws the switch into the position shown in Fig. 2 where it lights the lamp and it remains locked in this position until the miner again returns the lamp to the lamp house. In this position of the switch the terminal 20 is dead and therefore the miner cannot short circuit the battery by connecting the terminals 20 and 21 together. The movement of the switch just described can be made freely because it is not locked at this time, the dog being arranged to lock the switch 12 in one position only.

It will now be appreciated that the invention provides a very simple switch construction and locking device which effectually prevents the operation of the switch by unauthorized persons but which is readily operable by. an attendant having a proper equipment. The parts are simple in construction, can be manufactured economically, and both the switch and the locking device are sturdy and substantial in construction so that the apparatus is extremely reliable.

IVhile I have herein shown and described the best embodiment of my invention that I have so far devised, it will be evident that the invention may be embodied in other forms Without departing from the spirit and scope thereof.

What I claim as new s:

1. In an apparatus of the character described, the combination of an electric switch comprising a switch member movable from one position to another, and inaccessible means for locking said member against unauthorized operation, said means being arranged to be released by placing a magnet in a readily accessible and substantially predetermined relationship to said means.

2. In an apparatus of the character described, the combination of an electric switch and a concealed lock for said switch arranged to be released by the application of a magnet to a readily accessible part of the apparatus.

3. In an apparatus of the character described, the combination of an electric switch, a casing in which said switch is located, and a lock for said switch located in said casing and releasable magnetically from outside the casing.

4. In an apparatus of the character described, the combination of an electric switch comprising a switch member movable from one position to another, a casing in which said member is located, a lock for said member, and a spring for holding said lock in its operative position, said lock being located .in said casing and being arranged to be released by the field of a magnet placed. in a substantially predetermined position at the outside of the casing.

5. In an apparatus of the character de scribed, the combination of an electric switch comprising a switch member movable from one position to another, a casing in which said member is located, a lock for said member, a spring forholding said lock in its operative position, said lock being located in said casing, and means for conducting magnetic lines of force substantially to the lock from a magnet placed at the outside of. said casing to release the lock..

6. In an apparatus of the character described, the combination of an electric switch comprising a pivoted switch. member, contacts cooperating therewith, a casing in which said member and contacts are mounted, a spring-pressed dog mounted in said casing and arranged to engage said member to lock it, said dog having an extension, and a part in said casing for conducting magnetic lines of force from a magnet placed against the outside of the casing substantially to said extension to withdraw said dog and thereby release said member. 7. In an apparatus of the character described, the combination of an electric switch 

